页岩气压裂返排液的碱活化过硫酸钠氧化技术

Alkali-activated sodium persulfate oxidation technology for shale gas flowback water

目的针对高盐难降解的页岩气压裂返排液,探究了碱活化过硫酸钠(NaOH/PS)氧化有机物的可行性。方法进行了过硫酸钠(PS)投加量、初始pH值、PS投加方式的单因素实验,进行了总有机碳(TOC)去除率动力学方程的拟合,开展了NaOH/PS体系反应机理的分析。结果NaOH/PS氧化页岩气压裂返排液最佳反应条件为PS质量浓度1500 mg/L,初始pH值为12,PS分4次投加,TOC去除率符合准二级反应动力学。通过EPR及淬灭实验,发现NaOH/PS氧化体系中的活性物质为SO_(4)^(-)·和OH·。结论研究结果可为页岩气压裂返排液中有机物去除装置的设计和运行提供参考。

Objective The aim was to explore the feasibility of removing organic matter in high saline and refractory shale gas flowback water through oxidation by alkaline activated sodium persulfate(NaOH/PS).Methods Single-factor analysis of PS dosage,initial pH value and PS dosage were performed,while the kinetic equations of TOC removal rate and the reaction mechanism of NaOH/PS system were investigated.Results The results showed that the optimal reaction conditions of NaOH/PS oxidation shale gas flowback water are as follows:PS concentration at 1500 mg/L,initial pH value at 12,PS added four times;and organic matter degradation could be described by quasi-second-order reaction kinetics.EPR and quench experiments showed that the active substances in NaOH/PS oxidation system were SO_(4)^(-)·and OH·.Conclusions This study could serve as the reference for the design and operation of organic matter removal units in the shale gas flowback water treatment process.